import 'dart:io';

main(List<String> args) {
  print("1");
  var result = getNetWorkData();
  result.then((value) {
    print("结果：$value");
  });
  print("3");
}

Future getNetWorkData() {
  return Future(() {
    sleep(Duration(seconds: 5));
    return "请求成功";
  });
}
